Paris, 1830. Fleur de Marie is rescued from poverty by the mysterious Rodolphe, who is in fact the Grand Duke of Gérolstein, who has gone incognito in search of an illegitimate child he once had. Which is not at all to the taste of Sarah Mac Gregor, her current mistress who kidnaps Fleur and has her locked up in Saint-Lazare prison.

Energetic priest Don Camillo returns to the town of Brescello for more political and personal duels with Communist mayor Peppone.

Willy Ferrière is a gambler living beyond his means, and his mistress is as greedy as he's dead broke. One day, he says out of loud in a a Montparnasse café that he would give 100,000 francs to get rid of his wealthy aunt so he could claim his inheritance. Someone secretly lets Willy know it's a deal. The old lady is murdered, and a low-life criminal is manipulated to be the perfect suspect. But Superintendant Maigret feels something is wrong.